1. Field of the Invention
The present invention relates to a stopper removing apparatus for automatically removing a sealing stopper from, for example, a blood sample tube and test tube.
2. Description of the Related Art
In a clinical assay field, for example, a glass type vacuum blood sample tube has been generally extensively used as a means for holding a material to be examined. For the vacuum blood sample tube, a sealing stopper, such as a rubber stopper, is used so as to maintain an interior vacuum level of the blood sample test tube stable and constant for an extended period of time. After the sampling of the blood, the material is subjected to the action of a centrifuge and transferred to an analytical unit, but, prior to taking up the material from the blood sample tube, a fitted stopper is removed from the blood sample tube. Conventionally, the removal of the stopper has been achieved by manually applying a twist force to the stopper or through the utilization of a twist-applying unit.
An automatic stopper removing device is disclosed, for example, in JPN PAT APPLN KOKAI Publication 1-263558, JPN UM APPLN KOKAI Publication 2-128949, etc. In the former Publication, the stopper is removed from the tube by applying a twist force to the stopper, while in the latter Publication, the stopper is removed from the tube by applying an upwardly oblique pull-up force to the stopper.
As set out above, the sealing stopper is conventionally removed from the vacuum blood sample tube, etc., by applying an external force to the stopper by the manual operation of the operator or applying a twist force to the stopper by the twist applying unit.
Such a stopper is firmly forced into the vacuum blood sample tube and an adequately strong force is required to remove the stopper from the tube. If there is no adequate ingenuity in properly removing the stopper from the tube, then there is risk that the blood sample tube will be broken or that a material in the tube will be scattered abruptly upon sudden removal of the stopper from the tube.
In the case where, in particular, the stopper is removed from the tube by the manual operation of the operator, there is, sometimes, a risk that the operator will receive a wound when the tube is scattered to fragments or that the scattered fragments will hit against the wound. Among those materials held in the tubes, some is contaminated with a highly infection virus, for example, in hepatitis and AIDS, and the operator has high risk of being infected with some diseases. In a blood assay, it is desirable to use an automatic stopper removing device for always automatically removing a sealing stopper from the tube without the operator's manual intervention.
If any scattered fragments from one blood sample tube enter into another, contamination is produced from the fragments and there is sometimes a case where no correct assay can be conducted on a blood analysis apparatus. Therefore, the stopper removing operation may affect the reliability with which blood is analyzed.